南京冬季重霾天气过程与颗粒物污染特征  

Weather Process and Particulate Pollution Characteristics during a Winter Haze Episode in Nanjing

作　　者：陈杨[1,2] 汤莉莉[2] 王壮[1] 秦玮[2] 葛顺[2] 周宏仓[1] 魏建苏[3] 张运江[1] 江蓉馨 

机构地区：[1]江苏省大气环境监测与污染控制高技术研究重点实验室,南京信息工程大学环境科学与工程学院,江苏南京210044 [2]江苏省环境监测中心,江苏南京210036 [3]江苏省气象局,江苏南京210008

出　　处：《环境科学与技术》2015年第6期74-82,共9页Environmental Science & Technology

基　　金：江苏省科技支撑计划项目(BE2012771);江苏省高校自然科学重大基础研究项目(11KJA170002);江苏省基础研究计划(自然科学基金项目)(BK2012884);江苏省环境监测科研基金项目(1016)

摘　　要：2013年12月1-9日利用常规气象观测资料和NCEP再分析资料,结合气态污染物和颗粒物化学组分外场观测,对2013年1月11-16日南京冬季一次持续重霾天气过程与颗粒物污染特征进行分析。结果表明,此次重霾过程,南京地面相对湿度较高且伴随静小风,近地层的水平输送条件较差,污染物不易扩散;天气环流形势稳定,地面受高压控制且处于均压场内,垂直方向存在明显逆温,为霾的形成提供有利的气象条件;大气PM10和PM2.5的小时最大浓度分别高达433μg/m3和325μg/m3,水平能见度低于1 km。PM2.5平均占PM10的72.4%,PM1平均占PM2.5的50.6%,颗粒物以细粒子为主,且PM2.5对能见度的影响随相对湿度的增加而减弱。水溶性离子SO42-、NO3-、NH4+是PM2.5中的主要成分,其占总浓度61%,同时SO2转化率(SOR)和NO2转化率(NOR)分别为0.35和0.31,表明霾天更有利于二次气溶胶转化。此外,PM2.5中无机盐的主要存在形式有(NH4)2SO4、NH4NO3以及少量NH4Cl。水溶性离子浓度与能见度呈现明显负相关性,说明PM2.5中水溶性离子对能见度的降低起主要作用。A long-lasting haze episode occurred in Nanjing from January 11 to 16, 2013. Based on the analysis of NCEP reanalysis data, conventional meteorological observation data and aerosol pollution monitoring data, effects of meteorological factors, circulation background, stability of stratification, and atmospheric particulates/chemical composition on the formation mechanisms and possible sources of this long-lasting haze episode were investigated. During the long-lasting haze, the transport and diffusion of air pollutants were suppressed because of very low wind speed and high humidity; atmosphere circumfluence was stable, ground was controlled by a high-pressure system and surface pressure gradients, and there existed continuous inversion temperatures in the vertical direction. These meteorological conditions were favorable for the haze formation. The maximum hourly concentrations of PM10 and PM2.5 were 433 and 325 μg/m^3, the visibility is less than 1 kin. PM1 and PM2.5 on average accounted for 72.4% and 50.6% of PM10 and-PM2.5 respectively, which means that fine particles contribute largely to the mass concentration of PM10. In addition, the impacts of PM25 on the visibility decrease with an increase of RH. Three water-soluble ions （WSII, i.e., SO4^2-, NO3^-, NH4^＋） on average accounted for 61% of PM2.5, and the conversion rates were 0.35 and 0.31 for SOs （SOR） and NO2 （NOR） respectively, which implies that PM2.5 consisted mainly of chemical components from secondary transformation during the serious haze. The inorganic salts of PM2.5 exist in the form of （NHc）2SO4, NH4NO3 and NH4C1. In addition, the visibility displayed a significant negative correlation with WSH, implying that the mass concentrations of WSII dominated the visibility.

关 键 词：霾 气象条件 大气颗粒物 水溶性离子 南京 

分 类 号：X513[环境科学与工程—环境工程]